In data recording systems, a very desirable feature is the ability to immediately verify the accuracy of just-written data, a capability known as “read-while-write” or RWW. It is typically accomplished in magnetic tape recording systems by constructing a recording head to minimize the reception of the write signal by the adjacent read head. Two conventional approaches to this are, first, to physically separate the read and write heads by distances of more than about 1 mm for heads using the signal strengths typically required for conventional tape coercivities; and second, to interpose magnetic shielding materials between the heads.
Both of these approaches are technically effective, in part because they “fix the problem at the source,” but they increase the complexity of the head design and manufacture, and thus the cost of the head. In particular, mechanical assembly of the head is difficult. Also, the resultant head presents a “double bump” contour to the tape, which is more difficult to manufacture than “single bump” designs. The result is that known practical RWW heads are more than twice as expensive to manufacture as non-RWW single bump heads.
In this document, consistent with the known art, the term “single bump” refers to a head contour in which the tape and head physically contact each other in substantially a single region. The term “double bump” refers to a head contour in which there is a region of substantial non-contact between the tape and head, lying between two regions of physical tape/head contact.